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Supported Browsers

Supported Browsers

Starting with v1.1.10, you can now use browserslist to automatically configure supported browsers.

Usage

.swcrc
{
  "env": {
    "targets": {
      "chrome": "79"
    },
    "mode": "entry",
    "coreJs": "3.22"
  }
}

Options

targets

string | Array<string> | { [string]: string }, defaults to {}.

Describes the environments you support/target for your project. This can either be a browserslist-compatible (opens in a new tab) query (with limitations) (opens in a new tab):

.swcrc
{
  "env": {
    "targets": "> 0.25%, not dead"
  }
}

Or an object of minimum environment versions to support:

.swcrc
{
  "env": {
    "targets": {
      "chrome": "58",
      "ie": "11"
    }
  }
}

Example environments:

  • chrome
  • opera
  • edge
  • firefox
  • safari
  • ie
  • ios
  • android
  • node
  • electron

If targets is not specified, SWC uses browserslist to get target information.

path

  • string, defaults to current directory.
  • path specifies the directory to load the browserslist module and any browserslist configuration files. For example, .browserslistrc or browserslist field in package.json. This can be useful if your build system isn't in the root of your project.

mode

⚠️

The usage mode is currently not as efficient as Babel, iff you have a usage like "foo"["a" + "t"](). SWC does not evaluate the expression "a" + "t" and will not include the String.prototype.at polyfill.

skip

Define ES features to skip to reduce bundle size. For example, your .swcrc could be:

.swcrc
{
  "env": {
    "skip": ["core-js/modules/foo"]
  }
}

coreJs

  • string, defaults to undefined.
  • coreJs specifies the version of core-js to use, can be any core-js versions supported by swc. E.g., "3.22".

The option has an effect when used alongside mode: "usage" or mode: "entry". It is recommended to specify the minor version (E.g. "3.22") otherwise "3" will be interpreted as "3.0" which may not include polyfills for the latest features.

Additional Options

  • debug: (boolean) defaults to false.
  • dynamicImport: (boolean) defaults to false.
  • loose: (boolean) defaults to false. Enable loose transformations (opens in a new tab) for any plugins that allow them.
  • include: (string[]) can be a core-js module (es.math.sign) or an SWC pass (transform-spread).
  • exclude: (string[]) can be a core-js module (es.math.sign) or an SWC pass (transform-spread).
  • shippedProposals: (boolean) defaults to false.
  • forceAllTransforms: (boolean) defaults to false. Enable all possible transforms.
CompilationModules